A U.S. federal court in Virginia on Monday ruled individual health coverage requirement of Obama’s healthcare reform law unconstitutional. This is the first federal court to strike down the law.

U.S. District Judge Henry E. Hudson, a Republican appointed by former President George W. Bush, ruled that the Obamacare’s requirement that citizens buy health insurance or pay a penalty is unconstitutional.

The lawsuit was filed by Virginia Republican Attorney General Kenneth Cuccinelli, who was trying to defend a new state statute that made it illegal to force state residents to buy health insurance.

“This won’t be the final round, as this will ultimately be decided by the Supreme Court, but today is a critical milestone in the protection of the Constitution,” Cuccinelli said in a statement after the ruling.

The sweeping healthcare law, formally known as the Affordable Care Act, has been facing a host of legal challenges since Obama signed it in March, with the provision of “individual mandate” mostly targeted by opponents.

In two other lawsuits in Virginia and Michigan, federal judges upheld the same provision. A third lawsuit related to the constitutionality of the individual mandate is pending in Florida.

In a document released before the midterm elections last month, Republicans made repealing the healthcare law one of their top priorities. With their overwhelming victory in the elections, Republicans are expected to redouble their efforts to strike down the law after the new Congress convenes in January.

Analysts see the repeal of the entire healthcare law through Congress as something unlikely, given the fact that Democrats still control the Senate and Obama has the veto power. Instead, they believe Republicans have a better chance of stripping certain provisions off the reform package through legal procedures.